Matthew 6:20-22 (KJV)

But lay up for yourselves treasures in heaven, where neither moth nor rust doth corrupt, and where thieves do not break through nor steal:For where your treasure is, there will your heart be also.The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light.

What is it that you focus on, on a regular basis? What thoughts consume your mind for the better part of each day. What are you giving your best to? What comes first in your life?